Radial piston pumps or motors

ABSTRACT

A radial piston pump includes two recesses connected to the high pressure port with one recess arranged in proximity to the rotor face, to provide an axial force to counterbalance the axial force on the rotor from the high pressure port, and the other recess in proximity to the rotor shaft to provide a radial force to counterbalance the radial force from high pressure liquid in the bores in the rotor. The axial force and the radial force form two couples which have equal and opposite moments.

United States Patent Freeman [45 Apr. 25, 1972 [54] RADIAL PISTON PUMPSOR MOTORS 2,458,985 1/1949 Ferris et al ..91/492 3,096,723 7/1963Puryeak ....9l/485 [72] Invent G l England 2,506,974 5/1950 Sokensen..91/485, [73] Assignee: Joseph Lucas (Industries) Limited, Biri gEngland Primary Examiner-William L. Freeh [22] Filed: AP 21 1970Attorney-Holman & Stern [21] Appl. No.: 30,442 [57] ABSTRACT A radialpiston pump includes two recesses connected to the U.S. 4 I v pressureport with one recess arranged in proximity to {he l 1/06 rotor face, toprovide an axial force to counterbalance the [58] Field of Search ..91/485, 486, 487 axial force n the t m the highpressure port, and theother recess in proximity to the rotor shaft to provide a radialReferences Cited force to counterbalance the radial force from highpressure UNITED STATES PATENTS liquid in the bores in the rotor. Theaxial force and the radial v force form two couples whichhave equal andopposite mo- 3,044 .4l2 7/1962 Orshansky ...9l/492 mem 2,827,859 3/1958Crane ...91/492 2,620,733 12/1952 Overbelle ..91/485 l Clairn 3 DrawingiFigures PATENTEB APR 2 5 I972 SHEET 10F 2 WM 2 1 m,

mvuanoe 01% {M ATTQNEYS RADIAL PISTON PUMPS R MOTORS Thisinventionrelates to a radial piston pump or motor of the type comprising ahousing, a rotor including a disc portion within the housing and a shaftprojecting from the housing, said disc portion being formed withaplurality of radial bores and with transverse passages communicatingwith said pores respectively and opening on to one face of said discportion, a plurality of pistons slidable respectively in said bores, acam in the housing for causing the pistons to reciprocate in said boresas the rotor is rotated, and inlet and outlet ports in'the housing withwhichthe passages are successively brought into communication as therotor is rotated.

In a pump or motor of this type therotor is subjected to a radial forcecaused by the pressure of fluid in the bores and to an axially directedforce offset from the rotary axis and caused by the pressure of liquidin the passagesand in which ever of the ports is at high pressure. Theseforces cause some difficulty in providing suitablebearings for the rotorandit is an object of the invention to provide a pump or motor-of thekind specified in which the effect of these forces is overcome.

ln accordance'with the invention there is provided a pump or motor ofthe kind specified in which the housing is formed with first and secondrecesses in communication with the port which is at high pressureiri'use,s'aid first recess being arrangedso that the fluid thereinapplies a force to the shaft q is shown in the drawing by. the arrowR"equal and opposite to the radial force applied to the rotor by 1 highpressure fluid in said bores and at a position axially spaced from therotor, said second recess being arranged so that fluid therein appliesto the rotor a force equal and opposite to the force applied thereby byhigh pressure fluid in'the passages and the port which is at highpressure, at a position diametrically opposite the, port which is athigh pressure, the arrangement being such that the moments of the equaland opposite forces applied to the rotor are equal and opposite.

In the accompanying drawings:-

FIG. 1 is a section through oneexample of a pump in accordance with theinvention; and

FIGS. 2 and 3 are sections respectively taken on lines 2--2and3--3ofFlG.1.' i

The pump shown includes a housing 10in three parts 11, 12 and 13. Thepart 11 comprises a disc portion'lla, a rim portion llb and a bossportion He. The rim portion 11b is coaxial with the disc portion 11a butthe boss portionllc is 011- set. The rim portion 11b is formedinternally with a cam track 14.

The housing part 12 is formed with an inlet port 15 and an outlet port16. The outlet port 16 has associated with it a kidmy shaped flat member17. The housing part 13 forms in combination with the housing part 12 acasing for a centrifugal impeller 18 by means of which fluid is causedto flow from the inlet 19 of the pump to the inlet portlS.

The housing rotatably supports a rotor 20. This rotor consists of a discportion 21 which lies within the cam track 14, a shaft portion 22projecting from one face of the disc portion and an auxiliary shaftportion 22a projecting from the other side of the disc portion 21 andsupporting the impeller 18. The disc portion 21 is formed with radialbores in which pistons 23 are slidably mounted. Each piston 23 carriesat its radially outer end a slipper 24 which engages the cam track 14.The face of the disc portion 21 remote from the shaft portion 22 isformed with passages which can communicate with the outlet port 16through openings in the member 17. The arrangement is such that, in use,the bores in the disc portion 21 can draw in fluid from the inlet port15 as the pistons 23 are moving outwardly, which occurs over half ofeach revolution. Over the and can cause liquid to bedisplaced throughthe openings in the member 17 and through the outlet port 16. it willappreciated that over the half revolution during which the pistons aremoving inwardly there will be .high pressure present in the bores andhence in the passages which communicate with the outlet port 16. Thusthere is a radial force applied to the disc portion 21 with its line ofaction as indicated by the arrow R in Fl G.. 1. Also an axial force isapplied to one face of the disc portion 21 with its line of action,indicated by arrow A in FIG. 1 offset from the axis of the rotor by adistance r.

To counteract these out-of-balance forces there are provided within thepart 11 of the housing first and second recesses which are connected viadrillings 30in thehousing to the high pressure port 16. The first ofthese recesses, 25, is formed withinthe boss portion 11c so that fluidpressure in the recess 25 acts upon the shaft portion 22. The area andlocation of the recess 25 are suchthat the force applied to the shaftportion 22 is equal andopposite to the force R. The line of action ofthe force applied by fluid pressure in the recess 25 and the spacingbetween the lines of action R and R is a. The other recess 26 is ofarcuate form and acts upon the face of the rotor disc 21 opposite thatinwhich the passages which communicate with the ports 15, 16 are formed.This recess 26 is so disposed and of such dimensions that the pressureof fluid in the recess 26 applies an axial force A (which is equal andopposite to, the' force A) to the rotor at a position offset by distancer' (which is equal to r) from the axis in the opposite direction to thedirection r. Thearrangement is such that the'moment aR of a the radialforces is equal and opposite to the moment 2Ar of the axial forces sothe rotor'is held in equilibrium. a

Having thus described my invention what I claim as new and desire tosecure by Letters Patent is:

l. A radial piston type pump ormotor comprising a housing,

I a rotor including a disc portion within the housing and a shaft otherhalf of the revolution the pistonsare moving inwardly projecting fromthe housing, said disc portion being formed with a plurality of radialbores and with transversepassages communicating with said boresrespectively and opening onto one faceof said disc portion a pluralityof pistons slidable respectively in said bores, a cam in the housingoperatively related to the pistons to reciprocate the pistons in saidbores as the rotor is rotated and high and low pressure ports in thehousing into communication with which the passages are successivelybrought as the rotor is rotated the housing being formed with first andsecond recesses in communication with the high pressure pot, said firstrecess being disposed adjacent the shaft at a position axially spacedfrom the disc portion and has an efi'ective area such that high pressurefluid therein applies a radial force to the shaft equal and opposite toa radial force applied to the rotor by high pressure fluid in said boressaid radial forces having parallel lines of action spaced by a firstdistance from one another, said second recess being disposed adjacent aface of the disc portion opposite that on to which the transversepassages open and having an effective area such that high pressure fluidtherein applies to the'disc portion an axial force equal and opposite toan axial force applied thereto by high pressure fluid in the passagesand the high pressure port at a position diametrically opposite the highpressure port with respect to axis of the rotor, so that the axialforces have lines of action spaced by a second distance, and the productof the effective area of the first recess and the first distance beingequal to the product of the effective area of the second recess and thesecond distance so that the moments of the equal and opposite forcesapplied to the rotor are equal and opposite.

i 1 i i 11'

1. A radial piston type pump or motor comprising a housing, a rotorincluding a disc portion within the housing and a shaft projecting fromthe housing, said disc portion being formed with a plurality of radialbores and with transverse passages communicating with said boresrespectively and opening onto one face of said disc portion a pluralityof pistons slidable respectively in said bores, a cam in the housingoperatively related to the pistons to reciprocate the pistons in saidbores as the rotor is rotated and high and low pressure ports in thehousing into communication with which the passages are successivelybrought as the rotor is rotated the housing being formed with first andsecond recesses in communication with the high pressure pot, said firstrecess being disposed adjacent the shaft at a position axially spacedfrom the disc portion and has an effective area such that high pressurefluid therein applies a radial force to the shaft equal and opposite toa radial foRce applied to the rotor by high pressure fluid in said boressaid radial forces having parallel lines of action spaced by a firstdistance from one another, said second recess being disposed adjacent aface of the disc portion opposite that on to which the transversepassages open and having an effective area such that high pressure fluidtherein applies to the disc portion an axial force equal and opposite toan axial force applied thereto by high pressure fluid in the passagesand the high pressure port at a position diametrically opposite the highpressure port with respect to axis of the rotor, so that the axialforces have lines of action spaced by a second distance, and the productof the effective area of the first recess and the first distance beingequal to the product of the effective area of the second recess and thesecond distance so that the moments of the equal and opposite forcesapplied to the rotor are equal and opposite.